AN1149-3A Lumileds Lighting, LLC, AN1149-3A Datasheet - Page 6

• Manufacturer Part Number: AN1149-3A
• Description: Advanced Electrical Design Models
• Manufacturer: Lumileds Lighting, LLC

Figure 3.5A. Thermally Stabilized Luminous Flux
versus DC Forward Current for HPWx-xHOO LED
Emitter with Different System Thermal Resistances.
Figure 3.5A shows Equation #3.9A graphed as
a function of I
emitter with a nominal forward voltage (i.e., V
2.25 V at 70 mA). Values of R
°
and R
3.5A. Note that Figure 3.5A is the same as
Figure 3, “HPWA/HPWT xx00 Relative
Luminous Flux vs. Forward Current” graph, in
the SuperFlux LED Data Sheet.
C/W, m = 1.0, k = –0.0106, V
S NOM
= 6.4 ohms were used for Figure
F
and R
θ
JA
for an HPWA xH00 LED
θ
O NOM
JA TEST
= 1.802 V,
= 200
F
=
6
This section discussed the key concepts of
modeling the electrical, optical, and thermal
performance of LED signal lights. Equation #3.6A
is a combination of Equations #3.3 in AB20 3
and #3.8 in AB20 3 that can be used to calculate
the maximum forward current as a function of
ambient temperature and thermal resistance.
Note that this equation models Figure 4
(Maximum DC Forward Current versus Ambient
Temperature) on the SuperFlux LED Data Sheet.
Equations #3.7A, #3.8A, #3.9A, and #3.10A
show different combinations of equations #3.7 in
AB20 3, #3.8 in AB20 3, and #3.9 in AB20 3 in
order to model various thermal effects on the
light output of the emitter. Note that Equation
#3.10A models Figure 3 (Normalized Luminous
Flux versus Forward Current) on the SuperFlux
LED Data Sheet.